1. Field of the Invention
The present invention relates in general to the field of information handling system batteries, and more particularly to a system and method for charging plural information handling system batteries.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Portable information handling systems have grown increasingly popular with end users as such systems have become more powerful. Portable information handling systems integrate a display and an internal power source within in a portable housing so that the system operates independent of hard wire connections, such as for interfacing with external peripherals or power. Typically, portable information handling systems are equipped with an integrated lithium ion battery that holds a charge to power system components when the system is not coupled to an external power source. When the system is couple to an external power source, power in excess of that needed to run the system is used to charge the battery. A typical information handling system battery will hold enough charge to support system operation for three to four hours and will continue to hold a reasonable charge for more than a year of usage before needing replacement. In some portable information handling systems, the amount of available charge is effectively increased by using plural batteries. A switch in the information handling system power system selects a battery for use, whether charging or discharging, and changes between batteries based on the available charge.
One disadvantage to portable information handling systems is that, after a battery discharges, the system must typically interface with an external power source for an extended period of time to recharge the battery. In order to reduce charge time, information handling systems sometimes use charging techniques that vary based upon the amount of charge present in the battery. For example, one technique reduces charge time by applying a constant current for about an hour until approximately an 80% RSOC (Relative Status of Charge) and then using pulse charging to fully charge the battery, usually over a time period of about another hour. Thus, in dual battery systems, charging time for both batteries is often four hours. Although pulse charging provides reduced charging times, it also tends to have a negative impact on long term battery life due to the chemical reaction within the lithium ion battery cells. Information handling system batteries are often expensive to replace, so reduced battery life expectancy provides a negative end user experience, particularly since the charge life of a battery tends to shorten as the battery life expectancy is approached.